Well. This is the 'infamous' Boles Barrow. Why such a reputation? Because a bluestone, of the same ilk as those at Stonehenge, was allegedly found here. The thing is, the Boles Barrow is supposed to be much older than the periods when the blue stones were being chipped at and shuffled about at Stonehenge. One interpretation of this discrepancy is that the blue stones were on Salisbury plain all along, having been brought by glaciers.
Aubrey Burl was all for this idea in this 1999 article: britarch.ac.uk/BA/ba45/ba45int.html
But lots of people think the glacier idea is sheer poppycock. Where are all the other glacial erratics on the plain? And right, ice sheets only dropped a dozen or so bluestones? Still, it's pretty bonkers that prehistoric people might have transported stones all the way from West Wales.
The stone in question was found by William Cunnington when he excavated the barrow in 1801. He wrote about a "Blue hard stone ye same as the upright Stones in ye inner circle at Stonehenge". The stone apparently eventually turned up in the Salisbury museum. But is it really the stone from the Boles barrow? And if so is it actually the same type of stone as the Stonehenge bluestones? If it is, could it have been brought earlier? With all the others, maybe? And the rest were later moved to Stonehenge? After all a small lump has recently been found at Woodhenge.
stonepages.com/news/#2037
Oh it's all very confusing.
Just to be helpful, the information on the EH scheduled monument record via Magic doesn't mention the stone at all.
The barrow's also been called Heytesbury I, and is now on the SMR and OS map as 'Bowl's Barrow'. I assume it's the same place though! If you look at it on Google Earth you'll see the poor thing looking like a roundabout surrounded by tyre/tank? tracks. In fact, I spotted this quote:
"... the scale and nature of military interference is startling. [C.C.] most vividly remembers his first visit to Bowl's Barrow, one of the most important spot sites in the SPTA, where he found recent tracked-vehicle marks scouring deeply through its ditch and the "no-driving" sign squashed into the mud of the new track."
(from Managing for Effective Archaeological Conservation: The Example of Salisbury Plain Military Training Area. By Roy Canham and Christopher Chippindale, in Journal of Field Archaeology, Vol. 15, No. 1 (Spring, 1988), pp. 53-65.)